1, a communication board in hand used three HCF4093 + MAX1487 into 485 communication equipment manufacturers supporting;

2, because want to use WiFi module (3.3 V TTL) communication, can't use it the communication board directly with the module of communication, at the same time by 74 hc14d + sp3485 conversion out 485 communication interface;
Design the circuit of the following

Design of the circuit on the other 5 VTTL equipment can normal communication,